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Hasan F Ates

Isik University, Electronics Engineer, Faculty Member

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Mehmet Hakan Hocaoglu

İstanbul Ticaret Üniversitesi

Suresh Muthusamy

Kongu Engineering College

Apcoms

State University of Jakarta

Yildiz Technical University

State University of Jakarta

Universitat Politecnica de Catalunya

Mahmoud Moghavvemi

University of Malaya, Malaysia

Politecnico di Milano

The University of Adelaide

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Papers by Hasan F Ates

Modeling Location Information for Wavelet-based Image Coding

Spherical coding algorithm for wavelet image compression

Image Processing, IEEE Transactions …, Jan 1, 2009

In recent literature, there exist many highperformance wavelet coders that use different spatiall... more In recent literature, there exist many highperformance wavelet coders that use different spatially adaptive coding techniques in order to exploit the spatial energy compaction property of the wavelet transform. Two crucial issues in adaptive methods are the level of flexibility and the coding efficiency achieved while modeling different image regions and allocating bitrate within the wavelet subbands. In this paper, we introduce the "spherical coder", which provides a new adaptive framework for handling these issues in a simple and effective manner. The coder uses local energy as a direct measure to differentiate between parts of the wavelet subband and to decide how to allocate the available bitrate. As local energy becomes available at finer resolutions, i.e. in smaller size windows, the coder automatically updates its decisions about how to spend the bitrate. We use a hierarchical set of variables to specify and code the local energy up to the highest resolution, i.e. the energy of individual wavelet coefficients. The overall scheme is nonredundant, meaning that the subband information is conveyed using this equivalent set of variables without the need for any side parameters. Despite its simplicity, the algorithm produces PSNR results that are competitive with the state-of-art coders in literature.

Rate-distortion and complexity optimized motion estimation for H. 264 video coding

Circuits and Systems for Video …, Jan 1, 2008

H.264 video coding standard supports several inter-prediction coding modes that use macroblock (M... more H.264 video coding standard supports several inter-prediction coding modes that use macroblock (MB) partitions with variable block sizes. Rate-distortion (R-D) optimal selection of both the motion vectors (MVs) and the coding mode of each MB is essential for an H.264 encoder to achieve superior coding efficiency. Unfortunately, searching for optimal MVs of each possible subblock incurs a heavy computational cost. In this paper, in order to reduce the computational burden of integer-pel motion estimation (ME) without sacrificing from the coding performance, we propose a R-D and complexity joint optimization framework. Within this framework, we develop a simple method that determines for each MB which partitions are likely to be optimal. MV search is carried out for only the selected partitions, thus reducing the complexity of the ME step. The mode selection criteria is based on a measure of spatiotemporal activity within the MB. The procedure minimizes the coding loss at a given level of computational complexity either for the full video sequence or for each single frame. For the latter case, the algorithm provides a tight upper bound on the worst case complexity/execution time of the ME module. Simulation results show that the algorithm speeds up integer-pel ME by a factor of up to 40 with less than 0.2 dB loss in coding efficiency.

Hierarchical quantization indexing for wavelet and wavelet packet image coding

Signal Processing: Image Communication, Jan 1, 2010

In this paper, we introduce the quantization index hierarchy, which is used for efficient coding ... more In this paper, we introduce the quantization index hierarchy, which is used for efficient coding of quantized wavelet and wavelet packet coefficients. A hierarchical classification map is defined in each wavelet subband, which describes the quantized data through a series of index classes. Going from bottom to the top of the tree, neighboring coefficients are combined to form classes that represent some statistics of the quantization indices of these coefficients. Higher levels of the tree are constructed iteratively by repeating this class assignment to partition the coefficients into larger subsets.

An adaptive edge model in the wavelet domain for wavelet image coding

Signal Processing: Image Communication, Jan 1, 2005

3-D Mesh Geometry Compression with Set Partitioning in the Spectral Domain

Circuits and Systems for Video …, Jan 1, 2010

This paper explains the development of a highly 1 efficient progressive 3-D mesh geometry coder b... more This paper explains the development of a highly 1 efficient progressive 3-D mesh geometry coder based on the region 2 adaptive transform in the spectral mesh compression method. A 3 hierarchical set partitioning technique, originally proposed for 4 the efficient compression of wavelet transform coefficients in high-5 performance wavelet-based image coding methods, is proposed 6 for the efficient compression of the coefficients of this transform. 7 Experiments confirm that the proposed coder employing such a 8 region adaptive transform has a high compression performance 9 rarely achieved by other state of the art 3-D mesh geometry 10 compression algorithms. A new, high-performance fixed spectral 11 basis method is also proposed for reducing the computational 12 complexity of the transform. Many-to-one mappings are em-13 ployed to relate the coded irregular mesh region to a regular mesh 14 whose basis is used. To prevent loss of compression performance 15 due to the low-pass nature of such mappings, transitions are 16 made from transform-based coding to spatial coding on a per 17 region basis at high coding rates. Experimental results show 18 the performance advantage of the newly proposed fixed spectral 19 basis method over the original fixed spectral basis method in the 20 literature that employs one-to-one mappings. 21 Index Terms-Computer graphics, data compression, data 22 visualization, transform coding, virtual reality. 23 86 thonormal Laplacian basis derived from mesh topology. In the 87 spectral compression method of [13], most of the coefficients 88 with low presumed energy are discarded, and the rest are 89 entropy coded. This coder is embedded to some extent because 90 increasing the number of coded/decoded coefficients allows 91 for progressive reconstructions at increasing fidelity levels. 92 The extensions in [18]-[20] attempt to reduce the transform 93 complexity or to improve the visual quality. 94 This paper solely addresses geometry coding since recent 95 research has largely focused on it and the coordinate values 96 contribute the greater fraction of the 3-D mesh information. 97 The entire connectivity information is assumed to be coded 98 in advance as in [13], [28], and [29] and facilitates the 99 single resolution, lossy coding of the geometry information 100 by the proposed coder. The proposed coder primarily supports 101 triangular faces that are the common denominator of rendering 102 tools in graphics hardware and software. 103 The geometry coder proposed in this paper is depicted 104 in Fig. 1. Surface partitioning limits the complexity of the 105 transform of [13] for a large surface mesh and facilitates the 106 local surface properties to be better captured for compression 107 purposes since the transform for each region is adaptively 108 designed. As in [13], the MeTiS software package [23] is also 109 used here for multi-level graph-based mesh partitioning. 110 We first propose that the transform coefficients for all the re-111 gions be bitplane coded with the color set partitioning embed-112 ded block coder (CSPECK) algorithm [22] with a motivation 113 similar to that of [14], [15], and [29]. The CSPECK algorithm 114 is based on SPECK, the low complexity, high-performance 115 wavelet-based greyscale image compression algorithm that 116 was integrated into the JPEG 2000 standard as subband 117 block hierarchical partitioning (SBHP). CSPECK processes 118 the coefficients in an order dictated by their magnitudes using 119 a set partitioning method and makes implicit bit allocation 120 to each space coordinate or mesh region possible. The more 121 accurate bit priorities yield a truly embedded bitstream. In 122 addition, since the dependencies among the most significant 123 bits of multiple coefficient magnitudes can be exploited by 124 coding multiple insignificant bits with a single symbol, high 125 compression performance can be attained. 126 A second important contribution of this paper is a modifi-127 cation of the fixed spectral basis method of [18] toward a low 128 complexity and high-performance coding system. Although 129 the coding methods in [13]-[15] provide high compression 130 performance, their front end components such as the adaptive 131 transform and the semi-regular remesher are computationally 132 157

SAD reuse in hierarchical motion estimation for the H. 264 encoder

Acoustics, Speech, and Signal …, Jan 1, 2005

The adoption of multiple macroblock partitions with variable block sizes is one of the main reaso... more The adoption of multiple macroblock partitions with variable block sizes is one of the main reasons behind the superior coding efficiency of H.264 video coding standard. Unfortunately, in motion estimation phase, repeating Sum of Absolute Difference (SAD) calculations for every possible block size incurs a heavy computational cost for the encoder. In this paper, in order to reduce the encoder complexity, we propose a hierarchical block matching based motion estimation algorithm that uses a common set of SAD computations for motion estimation of different block sizes. Based on the hierarchical prediction and the median motion vector predictor of H.264, the algorithm defines a limited set of candidate vectors; and the optimal motion vectors for all partitions are chosen from this common set. Simulation results show that hierarchical estimation with SAD reusing reduces the total computations by a factor of 17.6 with slight loss in coding efficiency.

Rate-distortion and complexity joint optimization for fast motion estimation in H. 264 video coding

Image Processing, Jan 1, 2006

Page 1. RATE-DISTORTION AND COMPLEXITY JOINT OPTIMIZATION FOR FAST MOTION ESTIMATION IN H.264 VID... more

A high performance hardware architecture for an SAD reuse based hierarchical motion estimation algorithm for H. 264 video coding

In this paper, we present a high performance and low cost hardware architecture for real-time imp... more In this paper, we present a high performance and low cost hardware architecture for real-time implementation of an SAD reuse based hierarchical motion estimation algorithm for H.264 / MPEG4 Part 10 video coding. This hardware is designed to be used as part of a complete H.264 video coding system for portable applications. The proposed architecture is implemented in Verilog HDL. The Verilog RTL code is verified to work at 68 MHz in a Xilinx Virtex II FPGA. The FPGA implementation can process 27 VGA frames (640x480) or 82 CIF frames (352x288) per second.

Wavelet-based image compression by hierarchical quantization indexing

Proceedings of the European Signal …, Jan 1, 2009

In this paper, we introduce the quantization index hierarchy, which is used for efficient coding ... more In this paper, we introduce the quantization index hierarchy, which is used for efficient coding of quantized wavelet coefficients. A hierarchical classification map is defined in each wavelet subband, which describes the quantized data through a series of index classes. Going from bottom to the top of the tree, neighboring coefficients are combined to form classes that represent some statistics of the quantization indices of these coefficients. Higher levels of the tree are constructed iteratively by repeating this class assignment to partition the coefficients into larger subsets. The class assignments are optimized using a rate-distortion cost analysis. The optimized tree is coded hierarchically from top to bottom by coding the class membership information at each level of the tree. Despite its simplicity, the algorithm produces PSNR results that are competitive with the state-of-art coders in literature.

Encoder assisted video frame rate up-conversion

by Hasan F Ates and Burak Cizmeci

… Applications (SIU), Jan 1, 2011

... ENCODER ASSISTED VIDEO FRAME RATE UP-CONVERSION Burak C¸ izmeci ve Hasan F. Ates Elektrik-Ele... more

Understanding the future of video coding

IEEE MULTIMEDIA, Jan 1, 2005

In today&#x27;s world, a wide range of multimedia services has become an integral part of man... more

Spectral coding of mesh geometry with a hierarchical set partitioning algorithm

by Hasan F Ates and F. Gurgen

Signal Processing and …

We propose a progressive mesh geometry coder, which expresses geometry information in terms of sp... more We propose a progressive mesh geometry coder, which expresses geometry information in terms of spectral coefficients obtained through a transformation and codes these coefficients using a hierarchical set partitioning algorithm. The spectral transformation used is the one proposed in where the spectral coefficients are obtained by projecting the mesh geometry onto an orthonormal basis determined by mesh topology. The set partitioning method that jointly codes the zeroes of these coefficients, treats the spectral coefficients for each of the three spatial coordinates with the right priority at all bit planes and realizes a truly embedded bitstream by implicit bit allocation. The experiments on common irregular meshes reveal that the distortion-rate performance of our coder is significantly superior to that of the spectral coder of .

Block motion estimation using wavelet filtering

Acoustics, Speech, and Signal …, Jan 1, 2000

Page 1. BLOcĸ MOTION ESTIMATION USING WAVELET FILTERING Hasan F. Ates and Michael T. Orchard Elec... more

Fast inter-mode decision and selective quarter-pel refinement in H. 264 video coding

Acoustics, Speech and Signal Processing, 2008. …, Jan 1, 2008

Page 1. FAST INTER-MODE DECISION AND SELECTIVE QUARTER-PEL REFINEMENT IN H.264 VIDEO CODING Hasan... more

FAST ALGORITHM ANALYSIS AND BIT-SERIAL ARCHITECTURE DESIGN FOR SUB-PIXEL MOTION ESTIMATION IN H. 264

Journal of Circuits, Systems, …, Jan 1, 2010

The sub-pixel motion estimation (SME), together with the interpolation of reference frames, is a ... more

An Algorithm and Its Architecture for Half-Pixel Variable Block Size Motion Estimation

… International Conference on …, Jan 1, 2007

Abstract This paper presents an accurate half-pixel variable block size motion estimation algorit... more

A Cost-Efficient Bit-Serial Architecture for Sub-pixel Motion Estimation of H. 264/AVC (PDF)

This paper presents a new VLSI architecture for sub-pixel motion estimation in H.264/AVC encoder.... more

Low complexity inter-mode selection for H. 264

Image Processing, 2006 IEEE …, Jan 1, 2006

The coding efficiency of the H.264/AVC standard enables the transmission of high quality video ov... more The coding efficiency of the H.264/AVC standard enables the transmission of high quality video over bandwidth limited networks. Due to the use of multiple Macroblock (MB) partitions, the Motion estimation module has extremely high complexity that makes it unpractical for most real-time applications on resource-limited platforms such as hand held devices. In this paper we propose a novel algorithm that significantly reduces the encoding complexity while maintaining high rate distortion performance. The proposed method reduces the Motion estimation (ME) computational complexity by accurately predicting the optimal MB partitions and restricting the number of candidate modes based on a-priori probabilities computed from spatio-temporal information. The experimental results show that the speed up of UmHexagonS [1] (one of the most efficient ME algorithms) can be doubled while maintaining the coding efficiency of Full Search.

Wavelet image coding using the spherical representation

Image Processing, Jan 1, 2005

Page 1. WAVELET IMAGE CODING USING THE SPHERICAL REPRESENTATION Hasan F. Ates Dept. of Electronic... more

Modeling Location Information for Wavelet-based Image Coding

Spherical coding algorithm for wavelet image compression

Image Processing, IEEE Transactions …, Jan 1, 2009

In recent literature, there exist many highperformance wavelet coders that use different spatiall... more In recent literature, there exist many highperformance wavelet coders that use different spatially adaptive coding techniques in order to exploit the spatial energy compaction property of the wavelet transform. Two crucial issues in adaptive methods are the level of flexibility and the coding efficiency achieved while modeling different image regions and allocating bitrate within the wavelet subbands. In this paper, we introduce the "spherical coder", which provides a new adaptive framework for handling these issues in a simple and effective manner. The coder uses local energy as a direct measure to differentiate between parts of the wavelet subband and to decide how to allocate the available bitrate. As local energy becomes available at finer resolutions, i.e. in smaller size windows, the coder automatically updates its decisions about how to spend the bitrate. We use a hierarchical set of variables to specify and code the local energy up to the highest resolution, i.e. the energy of individual wavelet coefficients. The overall scheme is nonredundant, meaning that the subband information is conveyed using this equivalent set of variables without the need for any side parameters. Despite its simplicity, the algorithm produces PSNR results that are competitive with the state-of-art coders in literature.

Rate-distortion and complexity optimized motion estimation for H. 264 video coding

Circuits and Systems for Video …, Jan 1, 2008

H.264 video coding standard supports several inter-prediction coding modes that use macroblock (M... more H.264 video coding standard supports several inter-prediction coding modes that use macroblock (MB) partitions with variable block sizes. Rate-distortion (R-D) optimal selection of both the motion vectors (MVs) and the coding mode of each MB is essential for an H.264 encoder to achieve superior coding efficiency. Unfortunately, searching for optimal MVs of each possible subblock incurs a heavy computational cost. In this paper, in order to reduce the computational burden of integer-pel motion estimation (ME) without sacrificing from the coding performance, we propose a R-D and complexity joint optimization framework. Within this framework, we develop a simple method that determines for each MB which partitions are likely to be optimal. MV search is carried out for only the selected partitions, thus reducing the complexity of the ME step. The mode selection criteria is based on a measure of spatiotemporal activity within the MB. The procedure minimizes the coding loss at a given level of computational complexity either for the full video sequence or for each single frame. For the latter case, the algorithm provides a tight upper bound on the worst case complexity/execution time of the ME module. Simulation results show that the algorithm speeds up integer-pel ME by a factor of up to 40 with less than 0.2 dB loss in coding efficiency.

Hierarchical quantization indexing for wavelet and wavelet packet image coding

Signal Processing: Image Communication, Jan 1, 2010

In this paper, we introduce the quantization index hierarchy, which is used for efficient coding ... more In this paper, we introduce the quantization index hierarchy, which is used for efficient coding of quantized wavelet and wavelet packet coefficients. A hierarchical classification map is defined in each wavelet subband, which describes the quantized data through a series of index classes. Going from bottom to the top of the tree, neighboring coefficients are combined to form classes that represent some statistics of the quantization indices of these coefficients. Higher levels of the tree are constructed iteratively by repeating this class assignment to partition the coefficients into larger subsets.

An adaptive edge model in the wavelet domain for wavelet image coding

Signal Processing: Image Communication, Jan 1, 2005

3-D Mesh Geometry Compression with Set Partitioning in the Spectral Domain

Circuits and Systems for Video …, Jan 1, 2010

This paper explains the development of a highly 1 efficient progressive 3-D mesh geometry coder b... more This paper explains the development of a highly 1 efficient progressive 3-D mesh geometry coder based on the region 2 adaptive transform in the spectral mesh compression method. A 3 hierarchical set partitioning technique, originally proposed for 4 the efficient compression of wavelet transform coefficients in high-5 performance wavelet-based image coding methods, is proposed 6 for the efficient compression of the coefficients of this transform. 7 Experiments confirm that the proposed coder employing such a 8 region adaptive transform has a high compression performance 9 rarely achieved by other state of the art 3-D mesh geometry 10 compression algorithms. A new, high-performance fixed spectral 11 basis method is also proposed for reducing the computational 12 complexity of the transform. Many-to-one mappings are em-13 ployed to relate the coded irregular mesh region to a regular mesh 14 whose basis is used. To prevent loss of compression performance 15 due to the low-pass nature of such mappings, transitions are 16 made from transform-based coding to spatial coding on a per 17 region basis at high coding rates. Experimental results show 18 the performance advantage of the newly proposed fixed spectral 19 basis method over the original fixed spectral basis method in the 20 literature that employs one-to-one mappings. 21 Index Terms-Computer graphics, data compression, data 22 visualization, transform coding, virtual reality. 23 86 thonormal Laplacian basis derived from mesh topology. In the 87 spectral compression method of [13], most of the coefficients 88 with low presumed energy are discarded, and the rest are 89 entropy coded. This coder is embedded to some extent because 90 increasing the number of coded/decoded coefficients allows 91 for progressive reconstructions at increasing fidelity levels. 92 The extensions in [18]-[20] attempt to reduce the transform 93 complexity or to improve the visual quality. 94 This paper solely addresses geometry coding since recent 95 research has largely focused on it and the coordinate values 96 contribute the greater fraction of the 3-D mesh information. 97 The entire connectivity information is assumed to be coded 98 in advance as in [13], [28], and [29] and facilitates the 99 single resolution, lossy coding of the geometry information 100 by the proposed coder. The proposed coder primarily supports 101 triangular faces that are the common denominator of rendering 102 tools in graphics hardware and software. 103 The geometry coder proposed in this paper is depicted 104 in Fig. 1. Surface partitioning limits the complexity of the 105 transform of [13] for a large surface mesh and facilitates the 106 local surface properties to be better captured for compression 107 purposes since the transform for each region is adaptively 108 designed. As in [13], the MeTiS software package [23] is also 109 used here for multi-level graph-based mesh partitioning. 110 We first propose that the transform coefficients for all the re-111 gions be bitplane coded with the color set partitioning embed-112 ded block coder (CSPECK) algorithm [22] with a motivation 113 similar to that of [14], [15], and [29]. The CSPECK algorithm 114 is based on SPECK, the low complexity, high-performance 115 wavelet-based greyscale image compression algorithm that 116 was integrated into the JPEG 2000 standard as subband 117 block hierarchical partitioning (SBHP). CSPECK processes 118 the coefficients in an order dictated by their magnitudes using 119 a set partitioning method and makes implicit bit allocation 120 to each space coordinate or mesh region possible. The more 121 accurate bit priorities yield a truly embedded bitstream. In 122 addition, since the dependencies among the most significant 123 bits of multiple coefficient magnitudes can be exploited by 124 coding multiple insignificant bits with a single symbol, high 125 compression performance can be attained. 126 A second important contribution of this paper is a modifi-127 cation of the fixed spectral basis method of [18] toward a low 128 complexity and high-performance coding system. Although 129 the coding methods in [13]-[15] provide high compression 130 performance, their front end components such as the adaptive 131 transform and the semi-regular remesher are computationally 132 157

SAD reuse in hierarchical motion estimation for the H. 264 encoder

Acoustics, Speech, and Signal …, Jan 1, 2005

The adoption of multiple macroblock partitions with variable block sizes is one of the main reaso... more The adoption of multiple macroblock partitions with variable block sizes is one of the main reasons behind the superior coding efficiency of H.264 video coding standard. Unfortunately, in motion estimation phase, repeating Sum of Absolute Difference (SAD) calculations for every possible block size incurs a heavy computational cost for the encoder. In this paper, in order to reduce the encoder complexity, we propose a hierarchical block matching based motion estimation algorithm that uses a common set of SAD computations for motion estimation of different block sizes. Based on the hierarchical prediction and the median motion vector predictor of H.264, the algorithm defines a limited set of candidate vectors; and the optimal motion vectors for all partitions are chosen from this common set. Simulation results show that hierarchical estimation with SAD reusing reduces the total computations by a factor of 17.6 with slight loss in coding efficiency.

Rate-distortion and complexity joint optimization for fast motion estimation in H. 264 video coding

Image Processing, Jan 1, 2006

Page 1. RATE-DISTORTION AND COMPLEXITY JOINT OPTIMIZATION FOR FAST MOTION ESTIMATION IN H.264 VID... more

A high performance hardware architecture for an SAD reuse based hierarchical motion estimation algorithm for H. 264 video coding

In this paper, we present a high performance and low cost hardware architecture for real-time imp... more In this paper, we present a high performance and low cost hardware architecture for real-time implementation of an SAD reuse based hierarchical motion estimation algorithm for H.264 / MPEG4 Part 10 video coding. This hardware is designed to be used as part of a complete H.264 video coding system for portable applications. The proposed architecture is implemented in Verilog HDL. The Verilog RTL code is verified to work at 68 MHz in a Xilinx Virtex II FPGA. The FPGA implementation can process 27 VGA frames (640x480) or 82 CIF frames (352x288) per second.

Wavelet-based image compression by hierarchical quantization indexing

Proceedings of the European Signal …, Jan 1, 2009

In this paper, we introduce the quantization index hierarchy, which is used for efficient coding ... more In this paper, we introduce the quantization index hierarchy, which is used for efficient coding of quantized wavelet coefficients. A hierarchical classification map is defined in each wavelet subband, which describes the quantized data through a series of index classes. Going from bottom to the top of the tree, neighboring coefficients are combined to form classes that represent some statistics of the quantization indices of these coefficients. Higher levels of the tree are constructed iteratively by repeating this class assignment to partition the coefficients into larger subsets. The class assignments are optimized using a rate-distortion cost analysis. The optimized tree is coded hierarchically from top to bottom by coding the class membership information at each level of the tree. Despite its simplicity, the algorithm produces PSNR results that are competitive with the state-of-art coders in literature.

Encoder assisted video frame rate up-conversion

by Hasan F Ates and Burak Cizmeci

… Applications (SIU), Jan 1, 2011

... ENCODER ASSISTED VIDEO FRAME RATE UP-CONVERSION Burak C¸ izmeci ve Hasan F. Ates Elektrik-Ele... more

Understanding the future of video coding

IEEE MULTIMEDIA, Jan 1, 2005

In today&#x27;s world, a wide range of multimedia services has become an integral part of man... more

Spectral coding of mesh geometry with a hierarchical set partitioning algorithm

by Hasan F Ates and F. Gurgen

Signal Processing and …

We propose a progressive mesh geometry coder, which expresses geometry information in terms of sp... more We propose a progressive mesh geometry coder, which expresses geometry information in terms of spectral coefficients obtained through a transformation and codes these coefficients using a hierarchical set partitioning algorithm. The spectral transformation used is the one proposed in where the spectral coefficients are obtained by projecting the mesh geometry onto an orthonormal basis determined by mesh topology. The set partitioning method that jointly codes the zeroes of these coefficients, treats the spectral coefficients for each of the three spatial coordinates with the right priority at all bit planes and realizes a truly embedded bitstream by implicit bit allocation. The experiments on common irregular meshes reveal that the distortion-rate performance of our coder is significantly superior to that of the spectral coder of .

Block motion estimation using wavelet filtering

Acoustics, Speech, and Signal …, Jan 1, 2000

Page 1. BLOcĸ MOTION ESTIMATION USING WAVELET FILTERING Hasan F. Ates and Michael T. Orchard Elec... more

Fast inter-mode decision and selective quarter-pel refinement in H. 264 video coding

Acoustics, Speech and Signal Processing, 2008. …, Jan 1, 2008

Page 1. FAST INTER-MODE DECISION AND SELECTIVE QUARTER-PEL REFINEMENT IN H.264 VIDEO CODING Hasan... more

FAST ALGORITHM ANALYSIS AND BIT-SERIAL ARCHITECTURE DESIGN FOR SUB-PIXEL MOTION ESTIMATION IN H. 264

Journal of Circuits, Systems, …, Jan 1, 2010

The sub-pixel motion estimation (SME), together with the interpolation of reference frames, is a ... more

An Algorithm and Its Architecture for Half-Pixel Variable Block Size Motion Estimation

… International Conference on …, Jan 1, 2007

Abstract This paper presents an accurate half-pixel variable block size motion estimation algorit... more

A Cost-Efficient Bit-Serial Architecture for Sub-pixel Motion Estimation of H. 264/AVC (PDF)

This paper presents a new VLSI architecture for sub-pixel motion estimation in H.264/AVC encoder.... more

Low complexity inter-mode selection for H. 264

Image Processing, 2006 IEEE …, Jan 1, 2006

The coding efficiency of the H.264/AVC standard enables the transmission of high quality video ov... more The coding efficiency of the H.264/AVC standard enables the transmission of high quality video over bandwidth limited networks. Due to the use of multiple Macroblock (MB) partitions, the Motion estimation module has extremely high complexity that makes it unpractical for most real-time applications on resource-limited platforms such as hand held devices. In this paper we propose a novel algorithm that significantly reduces the encoding complexity while maintaining high rate distortion performance. The proposed method reduces the Motion estimation (ME) computational complexity by accurately predicting the optimal MB partitions and restricting the number of candidate modes based on a-priori probabilities computed from spatio-temporal information. The experimental results show that the speed up of UmHexagonS [1] (one of the most efficient ME algorithms) can be doubled while maintaining the coding efficiency of Full Search.

Wavelet image coding using the spherical representation

Image Processing, Jan 1, 2005

Page 1. WAVELET IMAGE CODING USING THE SPHERICAL REPRESENTATION Hasan F. Ates Dept. of Electronic... more